Resist compositions are facing new challenges in the field of microelectronic fabrications. The need to mass-produce microscopically dimensioned, etched configurations has resulted in demand for resists with the properties of greater speed, higher temperature resistance, and even more importantly, more rapid processing so as to reduce the unit cost of the end-product electronic device. ("Speed" as used herein refers to the sensitivity of the composition to activating radiation, and is not to be confused with development rates.) Chief among those properties that, prior to this invention, have retarded rapid processing, has been the long development time needed to remove the exposed resist. Slow development rates particularly retard the overall process if a plurality of resist exposures and developments are needed for a given electronic device.
Substituents, for example, organic acids, that might be expected to improve solubility in the developer, and therefore improve the development rate, may adversely affect other properties, such as the high temperature resistance, speed, or development latitude. Furthermore, substituents that are known to enhance temperature resistance have little predictability concerning their effect on development rates. It has been difficult, therefore, prior to the present invention to identify a sensitivity-enhancing agent that provides improved development rates as well as maintaining outstanding speed and temperature resistance.
U.S. Pat. No. 3,661,582 describes sensitivity-enhancing agents for positive-working E-beam resists and photoresists such as 1,2-quinone diazide esters, that enhance the speed of the resist composition. The sensitivity-enhancing agents comprise heterocyclic compounds, the nuclear atoms of which consist of carbon atoms and from 2 to 4 nitrogen atoms at least one of which is bonded to hydrogen. Of the large number of compounds described, 5-chloro-benzotriazole and 1H-benzotriazole are included. However, there is no recognition or suggestion in the aforementioned patent that any of the compounds described therein, with or without particular substituents, would provide enhanced development rates as well as maintain speed.